Friday, August 22, 2014

Using RE24 To Account For Situational Hitting

Tigers designated hitter Victor Martinez is adding runs with situational hitting
(Photo Credit: Bruce Hemmelgarn, USA Today Sports)

Many fans grumble that statistics such as OPS and Batting Runs do not account for situational hitting.  For example, if Tigers slugger Miguel Cabrera singles with a runners on second and third to drive home two runs, he gets the same credit as he would for a single with the bases empty.  Some will argue that this is not fair because he contributes more to his team in the former scenario than the latter.  In this post, I will re-introduce an under-utilized statistic which accounts for a hitter's performance in different circumstances. 

Traditional fans like to address situational hitting with the familiar Runs Batted In statistic, but that is a team dependent measure.  A player has more or less opportunity to drive in runs depending on who is batting in front of him.  Thus, a player gets acknowledged for driving home runs, but does not get penalized for failing to drive home runs.  So, the RBI count is not an adequate measure of situational hitting.

Other fans point to batting average with runners in scoring position, but that is based on a limited number of plate appearances.  It also doesn't consider the number of outs, the specific base runners (e.g. bases loaded versus second base only) or the type of hit (single, double, triple or home run).  Moreover, it ignores a player's performance when no runners are in scoring position.  

What we want is a statistic which gives a player credit for everything he does including situational hitting.  Batting Runs Above Average by the 24 Base/Out States (RE24) - found at FanGraphs - does just that.  The RE24 statistic is also sometimes referred to as "Value Added".  This metric will give a player credit for his singles, doubles, and all other events, and gives him extra credit for hits occurring with runners on base.  It even gives him points for a scenario which most other metrics ignore - moving a runner over with a ground out.  On the other hand, it subtracts extra points for hitting into double plays.

In past posts, I discussed just plain Batting Runs or Weighted Runs Above Average (wRAA or RAA) which is an estimate of how many runs a player contributed to his team beyond what an average hitter would have contributed in his place.  The RE24 metric is similar to RAA except that it uses base/out states in the calculation.  An example of a base/out state is "runners at first and third and one out".  There are 24 possible base/out states and RE24 takes all of them into consideration. 

In the calculation of RAA, a double with the bases loaded and two outs counts the same (0.770 runs) as a double with the bases empty and no outs.  Conversely, RE24 counts the bases loaded double more than the bases empty double (2.544 versus 0.632) because it does more to increase the expected runs scored in the inning.

The RE24 metric for one at bat gives us the difference between run expectancy at the beginning and end of a play.  For example, suppose Cabrera bats with a runner on first and one out. In that situation, we would expect 0.556 runs to score by the end of the inning.  Assume that Cabrera then doubles, putting runners on second and third with one out. In that situation, we would expect 1.447 runs to score by the end of the inning. Therefore, Cabrera's double is worth 0.891 runs.

Summing RE24 over all of a batter’s plate appearances yields his season total RE24. For
example, Cabrera has a RE24 of 30.7 this year.  So, by that measure, he contributed about 31 runs above what an average batter would have been expected to contribute given the same opportunities. This is higher than his 27.7 RAA, which means that Cabrera has been especially good in situations with high run expectancy and has added more to his team’s runs total than RAA indicates.  We can estimate that he has contributed an extra 3 runs with his situational hitting.

Since situational hitting is largely (although not completely) random, RE24 is less predictive than RAA and should not generally be used as a measure of ability based on one year of data.  It does become more predictive over multiple years and may be a more representative measure of ability over a career than RAA. Regardless of what it says about talent though, it is a good alternative to RAA for looking at past performance. 

Table 1 below shows that Angels center fielder Mike Trout (46.7) and Blue Jays left fielder Melky Cabrera (37.5) rank first and second in RFE24.  Cabrera's RE24 is 12 runs higher than his RAA which tells us that he has been very good in situations with high run expectancy.  On the flip side, Blue Jays slugger Jose Bautista has a differential of -10.8 (24.2 on RE24 versus 35.0 on RAA) suggesting that he does not do as well in spots where he has a greater chance to contribute runs.  

Table 1: AL RE24 Leaders as of August 21, 2014
Name
Team
RE24

RAA
RE24-RAA
Mike Trout
Angels
46.7
37.8
8.9
Melky Cabrera
Blue Jays
37.5
25.5
12.0
Victor Martinez
Tigers
34.5
31.4
3.1
Michael Brantley
Indians
33.6
29.2
4.4
Jose Abreu
White Sox
33.2
34.9
-1.7
Robinson Cano
Mariners
31.7
25.0
6.7
David Ortiz
Red Sox
31.4
22.9
8.5
Miguel Cabrera
Tigers
30.7
27.7
3.0
Adrian Beltre
Rangers
26.8
24.8
2.0
Jose Bautista
Blue Jays
24.2
35.0
-10.8
Josh Donaldson
Athletics
23.1
16.9
6.2
Edwin Encarnacion
Blue Jays
21.6
28.6
-7.0
Kyle Seager
Mariners
21.0
18.4
2.6
Alex Gordon
Royals
20.6
17.6
3.0
Brandon Moss
Athletics
19.5
15.5
4.0
Conor Gillaspie
White Sox
17.9
12.9
5.0
Adam Eaton
White Sox
17.3
10.7
6.6
Lonnie Chisenhall
Indians
16.7
12.9
3.8
David Murphy
Indians
16.2
1.0
15.2
Jacoby Ellsbury
Yankees
14.7
6.2
8.5
Data source: FanGraphs.com

Table 2 shows that designated hitter Victor Martinez (34.5), Miguel Cabrera (30.7) and outfielder J.D. Martinez (15.5) are the only Tigers regulars with above average numbers for RE24.  Using RAA, all of the regulars other than the shortstops are above average.  

Additionaly, Victor Martinez (3.1) and Cabrera (+3.0) are the only hitters with positive RE24-RAA differentials.  So, most of the Tigers are not doing so well in plate appearances where there is high run expectancy.  Most notably, catcher Alex Avila has a differential of -9.5 and right fielder Hunter -9.1.

Table 1: RE24 for Tigers as of August 21, 2014
Name
RE24

RAA
RE24-RAA
Victor Martinez
34.5
31.4
3.1
Miguel Cabrera
30.7
27.7
3.0
J.D. Martinez
15.5
19.1
-3.6
Rajai Davis
-1.4
4.2
-5.6
Ian Kinsler
-1.9
4.4
-6.3
Austin Jackson
-2.3
3.6
-5.9
Eugenio Suarez
-3.1
-0.9
-2.2
Torii Hunter
-3.2
5.9
-9.1
Nick Castellanos
-3.6
0.8
-4.4
Alex Avila
-7.8
1.7
-9.5
Andrew Romine
-17.6
-10.2
-7.4
Data source: FanGraphs.com

9 comments:

  1. Always enjoy your posts, Lee. Quick question - can these two stats be computed at the team level?

    ReplyDelete
  2. Why not just use WPA?

    ReplyDelete
  3. The problem with WPA is that it can be drastically affected by one really high leverage situation. For example, a game winning single in the ninth inning might count 50 times more than a solo home-run in the 8th inning of a 4-0 game. That's not fair because a player is getting a huge amount of credit for a situation he didn't create.
    WPA is great for determining things like the turning point of a game or the hero of a game, but not as good for describing seasonal performance.

    ReplyDelete
    Replies
    1. Guess I don't understand what you're saying. RE24 doesn't take overall game situation into account, just how many runs can be expected from an inning on average vs how much the player produced? Seems like your argument against WPA is that 'a player benefits too much from very high leverage performances', but considering those high leverage performances is what actually wins games, why are you so quick to discount it? Over the course of the season, a player's WPA over every batting event will average out. For example, Alex Avila has a rather high WPA vs other Tigers batters, but a low RE24. Isn't this saying, basically, that he contributes positively in important game situations, but is a below average hitter overall? Just seems that, intuitively, Miguel Cabrera will have a higher RE24 simply because he is an above average hitter, and looking at RE24 table, it does seem to simply list the Tigers hitters in order from good hitter to poor hitter. The better hitter you are, the better you will produce compared to an average hitter, the higher your RE24 will be. I guess I don't understand the point of RE24, then. We already know that situational hitting is generally not a skill- great hitters will simply produce above average results if the baseline is an average hitter- and will obviously produce more runs than average in an inning. I don't need RE24 to tell me that. Those only positive players in that table have really high wOBAs. The rest of them hover around average wOBA, and since the baseline is average- their RE24 isn't impressive.

      It's the same reasoning behind why Cabrera will rank low in something like fangraph's 'clutch' stat, where, again, someone like Avila ranks high in clutch because his performance in higher leverage situations is a great deal better than his overall batting line, whereas the difference between Cabrera's batting in normal situations and higher leverage situations is not that large. He's simply a great hitter overall, regardless of game situation- which is why his RE24 is high and his WPA is the best on the team, because he hits well all the time, and his position in the batting order puts him in situations to capitalize more often than not.

      Delete
    2. I'm not "dismissing it quickly". This is a topic that has been discussed a lot. I don't like using WPA to measure a player's season performance because I think it can give a player too much credit for succeeding in opportunities which he did not create by himself. I don't think it necessarily averages out over the course of a season. A player has limited opportunities to bat in the highest leverage situations and I don't want those situations weighted too heavily in a statistic which summarizes his season.

      I like RE24 because it gives a player credit for performing well in situations where he has the best chance to create runs without giving him an undue amount of credit which I think WPA does. I wouldn't use it to project into the future, but I think it's useful in looking at what he contributed to his team in the past.

      I don't agree that clutch hitting is not a skill. It's not a skill to the extent that some media and fans make it out to be, but if you look at a players entire career, there are some who are good at situational hitting and will consistently have a higher RE24 than RAA.

      Delete
  4. Tigers team stats: RE24 12.3 RAA 64.7. That's a pretty big difference.

    ReplyDelete
  5. Not that it really matters a lot due to less playing time, but I wouldn't mind seeing the Holaday and Kelly scores just to see how they rank comparatively.

    ReplyDelete
  6. TSE, you can find all the numbers at FanGraphs.com

    ReplyDelete
    Replies
    1. Ok I'll check it out, I was just trying to fish out the info and digress into more conversation about it. I don't spend much time on Fangraphs so wasn't really sure if it was available offhand. The majority of my extent of hunting for stat information on the internet has been pretty limited to just coming here for that stuff since you seem to adequately cover close to 100% of everything I'm really interested in anyhow, so thought it would just be easier to delegate that work to you! ;)

      Delete

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